en:developers:documentation:mac80211:tracing
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| + | ===== Driver API tracing ===== | ||
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| + | ==== Enabling ==== | ||
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| + | Since 2.6.32 mac80211 includes a tracing framework, and since 3.2 it is always enabled if possible (if EVENT_TRACING is enabled in the kernel.) | ||
| + | |||
| + | To be able to use it on kernels before 3.2, enable <code>CONFIG_MAC80211_DRIVER_API_TRACER</code> (requires tracing and <code>CONFIG_MAC80211_DEBUG_MENU</code>). | ||
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| + | ==== Using trace-cmd ==== | ||
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| + | The easiest way to give a trace to other people is to use trace-cmd, see also [[https://lwn.net/Articles/410200/|https://lwn.net/Articles/410200/]]. To record a trace with trace-cmd, use | ||
| + | <code>trace-cmd record -e mac80211</code> | ||
| + | This will record until you hit Ctrl-C to abort. The result is stored in a file "trace.dat" which you can send around for analysis. You should compress it before sending it to other people since it is relatively large but compresses well. | ||
| + | |||
| + | To analyse a file, use | ||
| + | <code>trace-cmd report -i trace.dat | less</code> | ||
| + | |||
| + | ==== cfg80211 and wpasupplicant ==== | ||
| + | |||
| + | Both cfg80211 and wpasupplicant have tracing support. Use '-e cfg80211' with trace-cmd to enable all cfg80211 tracing points. For wpasupplicant enable CONFIG_DEBUG_LINUX_TRACING build config and use -T switch to get log messages sent to the tracing framework. | ||
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| + | |||
| + | ==== Driver tracing ==== | ||
| + | |||
| + | In addition to mac80211, some drivers include tracing as well. | ||
| + | |||
| + | |||
| + | === iwlwifi === | ||
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| + | For iwlwifi, set the <code>IWLWIFI_DEVICE_TRACING</code> Kconfig option. You can then get new trace subsystems: | ||
| + | |||
| + | ; iwlwifi : the commands exchanged between driver and device | ||
| + | ; iwlwifi_io : the device IO accesses and interrupt information | ||
| + | ; iwlwifi_msg : all debug messages from the driver | ||
| + | ; iwlwifi_ucode : uCode events (not sure they're useful today) | ||
| + | ; iwlwifi_data : data for TX/RX frames | ||
| + | Recommended: | ||
| + | <code>trace-cmd record -e mac80211 -e mac80211_msg -e iwlwifi -e iwlwifi_msg -e iwlwifi_data</code> | ||
en/developers/documentation/mac80211/tracing.txt ยท Last modified: 2015/01/26 09:49 (external edit)
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